The invention relates to sign systems, and in particular illuminated sign systems.
Existing sign systems typically consist of a rectangular extruded metal frame supporting on one or both sides a translucent display face of rigid plastic or flexible material. The metal framework supports fluorescent lighting, which is the source of illumination. Typically in such sign systems the outer portion of the framework is hinged to permit access to the interior of the framework and allow the translucent face to be replaced. Examples of such sign systems are shown in U.S. Pat. Nos. 4,265,039, J. R. Brooks issued May 5, 1981, 4,267,657, W. Kloke issued May 19, 1981 and 4,542,605, James Gandy issued Sept. 24, 1985.
Such sign systems are intended to be mounted fairly permanently in an outdoor location, and do not allow the sign face to be readily changed. A skilled worker familiar with the sign system is required to carry out the change of the sign face.
Point-of-purchase advertising is found to be a very cost-effective method of advertising consumer products. A particularly effective form of point-of-purchase advertising is found to be the use of illuminated display signs showing the products of particular manufacturers to replace conventional aisle markers in grocery stores. For example, a sign merely indicating that a particular aisle number is the location of a particular food product can be replaced with an illuminated sign showing the aisle number and a photograph or color transparency of the food product of a particular manufacturer which is found on the aisle. Since the location and type of products in a grocery store is constantly changing, an illuminated sign for this purpose must necessarily allow quick and inexpensive changing of display faces. Signs which used rigid plastic faces prepared from color transparencies are found to be too expensive to be practical in this application.